Aspect Ratio Calculator
Find the aspect ratio of any width and height, and calculate a new height (or width) that keeps the exact ratio — ideal for images, video and responsive design. Includes presets like 16:9, 4:3 and 1:1.
Original size
Aspect ratio
16:9
(1.7778 : 1)
Resize keeping ratio
Enter a new width and the height that preserves the exact aspect ratio is calculated for you — perfect for images, video and responsive design.
🔒 This tool runs entirely in your browser. Your data is never uploaded.
Frequently asked questions
How does it keep the ratio?＋
It works out the ratio of your original width and height, then scales the new dimension by the same factor so the proportions stay identical.
What are the presets for?＋
Quick access to common ratios like 16:9, 4:3, 1:1 and 9:16 for video, photos and social posts.
Does it simplify the ratio?＋
Yes — it reduces the width:height to its simplest whole-number form using the greatest common divisor.